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When to plant Onion in Manatee County County,

Plant Onion in Manatee County County from January 7 to January 28 in spring. Manatee County County sits in USDA Zone 10a, with last frost around January 28 and first frost on December 20. A second sowing from October 25 to November 8 extends the harvest into fall.

When to Plant Onion in Manatee County, FL

Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.

Manatee County, Florida is in USDA Zone 10a. The average last spring frost is January 28 and the first fall frost is December 20, giving you a growing season of approximately 326 days.

At an elevation of 237 feet, Manatee County receives approximately 57.6 inches of rainfall annually with predominantly sand soil. Summer highs average 103°F, so Onion may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Onion will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Onion root diseases.

Manatee County, FL (Zone 10a) Year-round
326 days
Last Spring Frost January 28
326 growing days
First Fall Frost December 20

Manatee County Soil Profile

Soil Type

Sand

Soil pH

5-5.9

Drainage

Well Drained

Monthly Watering Guide for Onion

Onion needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Onion Needs Rainfall You Supplement Action
Jan 4.3" 2.6" 1.7" 💧 Light watering
Feb 4.3" 2.8" 1.5" 💧 Light watering
Mar 4.3" 3.3" 1" 💧 Light watering
Apr 4.3" 3" 1.3" 💧 Light watering
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 8.7" 0" ✅ Rainfall sufficient
Jul 4.3" 8.4" 0" ✅ Rainfall sufficient
Aug 4.3" 7.2" 0" ✅ Rainfall sufficient
Sep 4.3" 8.4" 0" ✅ Rainfall sufficient
Oct 4.3" 4.7" 0" ✅ Rainfall sufficient
Nov 4.3" 2.6" 1.7" 💧 Light watering
Dec 4.3" 2.2" 2.1" 💧 Light watering

Water needs are for active growing months only (Jan–Dec in Manatee County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Onion Planting Timeline — Manatee County, FL

Onion Planting Calendar

Activity When Date Range
Start Indoors December 31 Dec 31 – Jan 14
Transplant Outdoors January 28 Jan 28 – Feb 11
Direct Sow January 7 Jan 7 – Jan 28
Harvest April 29 Apr 29 – Jun 17
Fall Sowing October 25 Oct 25 – Nov 8

Plant 1" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors Transplant Outdoors Direct Sow
February Transplant Outdoors
March
April Harvest
May Harvest
June Harvest
July
August
September
October Fall Sowing
November Fall Sowing
December Start Indoors

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 10a

📆 Growing Season

326 days in Manatee County

Growing Tips for Manatee County

Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans
  • Asparagus

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Onion in Manatee County, FL?

Manatee County is in Zone 10a with an average last frost of January 28. Plan your Onion planting based on this frost date — see the calendar above for exact timing.

What planting zone is Manatee County, FL?

Manatee County, Florida is in USDA Hardiness Zone 10a. The average last spring frost is January 28 and first fall frost is December 20.

When should I plant Onion in Manatee County County, ?

In Manatee County County, , plant Onion after the last frost (around January 28) and before the first frost (around December 20). Best results when soil holds above 50°F.

What growing zone is Manatee County County, for Onion?

Manatee County County sits in USDA Zone 10a. Onion grows reliably in zones 3a through 10b, so it's a good fit here.

Can Onion grow in Manatee County County's climate?

Yes — Onion grows well in Manatee County County's temperate climate. Manatee County County averages a 327-day frost-free season, with last frost around January 28 and first frost around December 20.

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Your Manatee County Garden Planner — Free

A 22-page printable planner built for Manatee County (Zone 10a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Manatee County, FL. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.